The article considers the main sources of urban air pollution. The growth dynamics of vehicles in the city of Volgograd is shown. The law of the distribution of the concentration of carbon monoxide for a different category of roads (urban, regional and local values), both for the measured and calculated concentration of CO, is derived. It is shown that the concentration of CO on the curb of the roadway of different categories of highways is characterized by a mixed Gaussian distribution.

Keywords: carbon monoxide, category of highways, city significance, regional significance, local significance, main sources of pollution, primary areas, mixed Gaussian distribution, field studies, density function